The present invention relates to an airbag apparatus, and particularly to a cover for an airbag apparatus.
An airbag is a popular restraint apparatus for a passenger of a vehicle. One example of such an airbag is an airbag for a front seat passenger. It is commonly known that a passenger-side airbag apparatus for a vehicle is disposed within an instrument panel. Such an airbag apparatus comprises a box-shaped retainer which stores a folded airbag and an inflator for inflating the airbag. An upper opening of the retainer is covered with a cover which is attached to the instrument panel. A C-shaped tear line is formed on the cover so as to define a door portion. Upon collision of a vehicle, gas is injected into the airbag from the inflator. The airbag first expands inside the retainer, and the tear line tears due to the expansion force of the airbag. The door portion opens by turning on an imaginary line connecting both ends of the C-shaped tear line to form an opening for the airbag. The airbag then inflates from the opening into a passenger compartment of the vehicle to absorb shock applied to a passenger.
Further, there is known a seamless instrument panel which improves an appearance of the cover and the instrument panel. Such a seamless instrument panel is formed such that the cover and the instrument panel are integrally formed, an installation member is projectingly formed on a back surface of the instrument panel, and a groove-shaped tear line is formed along the installation member. Japanese Published Patent Application No. 2004-136698 discloses a typical seamless instrument panel which comprises a panel main body made of resin, an installation bracket made of resin, which is welded to the back surface of the panel main body. A tear portion of a closed-loop is formed on the back surface of the panel main body so as to define a door portion. The installation bracket comprises a cylindrical portion welded to an outer peripheral portion of the door portion, a reinforcement plate welded to a back surface of the door portion and a hinge portion connecting the cylindrical portion and the reinforcement plate. The hinge portion is formed into a U-shape in cross section so as to protrude toward the airbag.